FAA Proposes AD for Sandel ST3400

A proposed AD is aimed at owners of the Sandel ST3400 terrain awareness and warning system/radio magnetic indicator (TAWS/RMI). The action was prompted by a report of in-flight bearing anomaly caused by input signal fault and software error. The FAA wants owners of ST3400s to install new software and placard the system until the upgrade is installed. Comments on the proposed AD are due by April 24.